Thera Band Hand Exercisers are specially formulated exercisers provided in a progressive sequence of five translucent colors. They are used for post-surgical hand rehab as well as hand, finger and forearm strengthening. Hand Exercisers can be easily cleaned with soap and water, allow to air dry, then coat lightly with corn starch or baby powder. Rub powder between your hands, then rub on ball for an even coating. You can heat hand exercisers in the microwave in 5 second increments and test to find the ideal time for each microwave unit, usually no more than 20 seconds maximum. Or, Store your Hand Exerciser in the refrigerator for 1 ½ – 2 hours and perform exercises as prescribed.